Harold a



June 7, 1932. A, H cKs AIRPLANE IGNITION SYSTEM Filed March 22, 1950 2 Sheets-Sheet 1 I INVENTOR.

ATTORNEY.

H. A. HICKS 2 Sheets-Sheet 2 AIRPLANE IGNITION SYSTEM Filed March 22; 1930 June 7, 1932.

Hmmq

\ INVENTOR.

B Y o o I I ATTORNEY.

Patented June 7, 1932 UNITED STATES PATENT OFFICE HAROLD A. HI ICKS, OF DETROIT, MICHIGAN, ASSIGNOR TO FORD'MOTOR COMPANY, OF DEARBORN, MICHIGAN, A CORPORATION OF DELAWARE AIRPLANE IGNITION SYSTEM.

The object of my invention is to provide an lgnition system for airplane engines which will facilitate starting these engines and which will provide safety features heretofore unobtainable in connection therewith. More specifically, my invention amounts to a simple and improved means whereby the engine spark plugs are supplied with current sufficient to give a hot spark even while the engines are being slowly started.

A further object of my invention is to provide an airplane engine ignition system in which high tension magnetos are used for producing the ignition current for normal operation, and in which a source of high voltage current produced independently of these magnetos is provided for slow speed starting.

Still a further object of my invention is to provide an ignition system, especially adapted for use with a tri-motored airplane,

- which will have means associated with each engine for supplying the normal running ignition current and which will have a single independent means for supplying starting ignition current, this independent means being so arranged that it may be selectively coupled to each engine by the airplane pilot.

With these and other objects in view my invention consists in the construction, arrangement, and combination of the various parts of my improved device, as described in the specification, claimed in my claim, and illustrated in the accompanying drawings, in which:

Figure 1 shows a wiring diagram of my preferred ignition system, having a booster magneto used in connection therewith.

Figure 2 shows an elevation of the booster magneto and control panel used therewith.

Figure 3 shows an alternate means of generating high voltage current for starting which may be used in place of the booster magneto shown in Figure 2, and

Figure 4 shows an alternate wirin gram which may be employed if desire Referr ng to the accompanying drawings, I have used the reference numeral 10 to indicate generally ordinary high tension magnetos, one for each engine, used to supply igmdo with the large airplane dia- 1 tion current for one set of engine spark plugs.

A set of magnetos 11 are also provided, one for each engine, which operates a second set of plugs in the conventional manner. There are thus two magnetos associated with each engine.

I have shown Wires 12 extending from the ground terminal of each magneto to switches 13 disposed in the airplane cockpit so that either or both of the magnetos may be selectively grounded to stop the engine. A wire 14 extends from the common terminal .of these switches to the metal of the airplane to complete the ground circuit. Wires 15 form a continuation of the wires 12 and extend to a master ground switch 16 which when operated by the pilot grounds all of the engines simultaneously.

Each of the magnetos 11 are provided with terminals 17 which are electrically connected with a brush disposed on the magneto distributor rotor. The high frequency current which may be supplied to the terminals 17 is thereby distributed to the various engine cylinders in correct sequence and operates independently of the current generating equipment in the magneto proper.

Certain types of magnetos are made which generate a high current at very low armature speeds but these magnetos are notconsidered g to be as reliable as the ordinary type, due to the use of springs and other complicated apparatus therein. The ordinary high tension magneto does not supply suflicient current to start the engine unless it is rotated very rap idly and this is sometimes quite diflicult to engines now used. I have provided In my improved system hot spark indemeans for generating a very pendently of the speed of rotation of the engine and a meanswhich does not complicate the ordinary magneto nor detrimentally affeet its reliability. Insulated high tension wires 18 extend from the terminals 17 to the instrument board in the pilots cockpit where I have provided jacks 19 connected to the ends of each of these wires. These jacks are preferably mounted in a sub-panel 20 which is secured on the instrumentboard. I I

A high voltage current generator 21, or what I have termed a booster magneto, is provided beneath the pilots seat or within easy reach' of the pilot in the. cockpit. A crank 22 is geared to the armature of this magneto so that by rotating this cranka series of high voltage impulses are generated in a lead wire 23 which extends from this magneto to the sub-panel 20. I have provided a plug 24 secured to the end of this lead wire which may be inserted in any one of the jacks 19. r

The operation for starting'each engine consists in first throwing off the switches 13 and 16, then inserting the plug 24 in the jack connected to this engine, then rotating the crank 22, and then operating the engine starting motor. The high voltage current generated by the booster magneto 21 provides a series ofsparks for each of the spark plugs supplied by the magnetos 11, the voltage of such current being dependent upon the'speed at which the crank 22 is rotated. As soon as the engine starts under its own power the mag netos 10 and 11 rotate at sufficient speed to supply the normal ignition current. important feature in connection with this device is that only one booster magneto is provided for each plane regardless .of the number of engines employed so that the total extra weight is small.

Referring to Figure 3, I have shown means whereby planes having battery equlpment therein may be equipped with a device substituting the booster magneto 21. I have shown a battery 25 having one terminal grounded and the other connected to one terminal of a buzzer 26. The other terminal of this buzzer is connected through a; switch 27 with one of the primary terminals of a spark coil 28, the other coil terminal being grounded. A wire 29 extends from the high voltage winding of this coil to the sub-panel 20 similar to the wire 23. Thus, when the switch 27 is closed the buzzer 26 operates to send an intermittent primary current to the coil 28 which generates a high voltage current in the wire 29 similar to that generated in the wire 23 by the booster magneto. This equipment may be used in place of the booster magneto 21, if desired, although the booster. magneto has several inherent advantages, such as, its independence of batteries, its simplicity and reliability ofoperation, and its prevention of 'the engine kicking back.

Referring to Figure 4, I have shown an-. other arrangement whereby high voltage current is supplied for starting the engines. The battery 25, buzzer 26, and switch 27 are arranged in substantially the same manner as. shown in Figure 4, but the output from the buzzer 26 instead of connecting with the coil 28 is connected by a wire 30 with the com- 'mon terminal of-a multiple point switch 31.

.because the wires 32 extending from the the airplane pilot for selectively energlzmg of these units are adjacent only a very little high tension wiring is required. The advantage of the structure just described arises pilots cockpit to the engines are low tension leads and consequently no special care need be used in insulating them from the metal of the plane.

The operation of this device consistsin first throwing off the switches 13 and 16, then turning the switch 31 forming contact with the particular motor to be started, then closing the switch 27, and then rotating the engine. A low voltage intermittent current is thereby supplied to the primary winding of each spark coil 33.

Many advantages arise from the use of this device among which may be mentioned that additional reliability is obtained because the 90 magnetos used for normally operating the engine are of'a type wherein no springs or the like are used and have the highest reliability. Further, the starting current used with the device shown in Figures 1 and .2 is entirely under the control of the pilot. .5. safety feature also arises through the use of this device in that it is impossible to accidentally cause the engine to kick back.

Some changes may be madein the arrangement, construction, and combination of the various parts of my improved device without departing from the spirit of my inven-, tion, and it is my intention to cover by my claim, such changes as may reasonably be included within the scope thereof.

I claim as my invention: 7

An ignition system for internal-combustion engines especially adapted for use with an airplane propelled by a plurality of such engines comprising, a pair of hi h-tension magnetos mounted upon each 0 said engines, each pair of said magnetos being gear driven by itsrespective engine and each of said magnetos supplying ignition currentat normal operating speeds, a centrallylocated switch mechanism operable by the airplane pilot for selectively and concurrently grounding each of said magnetos to Stop each or all of said engines, a plurality of spark coils one for each of said engines,

each of said coils being mounted directly upon its respective engine, a battery, a centrally located starting switch operabl e by each of said coils by means of said battery,

and high-tension conductors extending from the spark coil-associated 'with each ofvsaid engines to the distributor rotor of one of the adjacent pair of magnetos, whereby energizk ing.

HAROLD A. HICKS. 

